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Re: My First PIG and it's operation



Hi Malcolm, coilers,
 Malcolm wrote:
>> Hi All,
><snip>
>>     If anyone could answer these questions I would be very grateful.
>> 1) Why only 10 mH with 130 turns on a 40 amp variac gapped core?
>
>Gapping a core will drop the induction factor (permeability of the 
>core) enormously. Most of the flux in a gapped core ends up in the 
>airgap and not the iron. The rationale for gapping in the first place 
>is to reduce core flux for a given applied magnetizing force. It also 
>turns the inductor into an efficient energy store. Ungapped cores 
>store little energy which is what you want in an ideal transformer.

An interesting tradeoff appears.  L goes down, but I^2 goes up (where 
'I' is the max current w/o saturation) E=0.5*L*I^2.  Seems that you want 
to maximize energy storage for whatever the max current your system 
would otherwise produce.  Else - you'd just use an air core (which 
doesn't saturate) and would allow a very large I...

Just rambling.

-Bill

Malcolm
<snip>

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